METHOD FOR THE PRODUCTION OF UREA OF HIGH MECHANICAL STRENGTH

摘要

It is known to add formaline to urea to increase its mechanical strength. Such process reduces the quality of the urea by increasing its water content. It is also known to reduce direct formation in urea prills by coating them with formaline. While this reduces dust it does not increase mechanical strength. The products produced by the known methods are not suitable for use with modern bulk handling. The present invention seeks to overcome this drawback by providing in the crystallization or evaporation method for the production of urea the improvement comprising incorporating into the urea prior to prilling a formaldehydepolymer having a formaldehyde content from 82 to 97% and a melting point from about 90 to 160.degree.C in an amount sufficient to provide 0.01 to 1% by weight based on the urea of formaldehyde.